This map of Pohakuloa, found in the plan, shows the radiation control areas in purple. The green triangle is the proposed Radiation Monitoring sample location. Co-located surface water and sediment samples will be gathered, the Army says.

The blue arrows indicate the direction of surface water flow, according to the Army. The sample location was selected based on the surface water hydrology.

The Army does not plan to sample groundwater at PTA, because they say the depth and limited precipitation make it unlikely that DU would migrate into the groundwater.

The Army plans to sample quarterly unless prevented by weather.

The controversy over DU heated up several years ago, when the Army admitted to the past use of Davy Crockett weapons system at PTA. In 2008, the Hawaii County Council even passed a resolution calling for the halt of live fire exercises at PTA until the hazards are mitigated.